Medical Conditions and Edema Quiz

Hemodynamic Disorders

• A collection of conditions affecting blood flow and circulation.
• Conditions include edema, thrombosis, embolism, infarction, hyperemia, congestion, hemorrhage, and shock.

Edema

• Definition: Excess fluid accumulation in extracellular or intracellular locations.
• Types:
  • Localized: Fluid buildup in a specific organ or body part (e.g., lung edema, ascites).
  • Generalized: Fluid buildup throughout the body (e.g., anasarca).
  • Special Types: Pulmonary and cerebral edema.

Water Distribution

• Approximately 60% of the body is water.
• Two-thirds of body water is intracellular.
• The rest is interstitial fluid (between cells).
• Only 5% is intravascular (within blood vessels).
• Edema involves a shift of fluid to the interstitial space.
• Examples of edema include hydrothorax, pericardial effusions, ascites, and anasarca.

Edema Pathogenesis

• Causes of Edema:
  • Increased hydrostatic pressure: Impaired venous return, congestive heart failure, ascites, venous obstruction, or external pressure.
  • Decreased oncotic pressure: Protein-losing nephropathies (e.g., nephrotic syndrome), liver cirrhosis, malnutrition, or malabsorption.
  • Lymphatic obstruction: Inflammatory, neoplastic, or postsurgical causes (e.g., breast cancer).
  • Sodium retention: Renal hypoperfusion leads to increased renin-angiotensin-aldosterone secretion.
  • Inflammation: Increased capillary permeability leads to edema, typically localized.

Thrombosis

• Definition: The formation of a solid mass of blood elements within a blood vessel or cardiac chamber in a living body.
• Example: Coronary thrombus.
• Hemostasis is the normal, rapid formation of a blood clot at the site of injury. Thrombosis is an abnormal activation of this process.
• Virchow's Triad:
  • Endothelial injury (e.g., smoking, hypercholesterolemia).
  • Stasis or turbulence of blood flow.
  • Hypercoagulability (primary or secondary).

Thrombosis Propagation, Dissolution & Organization

• Propagation: Thrombi can grow larger by the addition of platelets and fibrin.
• Embolization: Parts of the thrombus may dislodge and travel to other parts of the body.
• Dissolution: Newly formed thrombi may be dissolved by fibrinolytic factors but may become resistant over time due to fibrin polymerization.
• Organization: Older thrombi may undergo organization and recanalization.

Thrombi Composition and Location

• Thrombi are composed of fibrin, platelets, and red blood cells.
• Thrombi can form in arteries, veins, heart chambers, and heart valves.
• Types of thrombi:
  • Pale thrombi: Primarily formed of platelets.
  • Red thrombi: Primarily formed of blood clots.
  • Mixed thrombi: A combination of platelets and blood clots.
  • Septic thrombi: Contain microorganisms (bacteria).
  • Aseptic thrombi: Do not contain microorganisms.

Thrombi Morphology

• Lines of Zahn: Alternating pale layers of platelets and fibrin with darker layers of red blood cells.

Embolism

• Definition: An embolus is an insoluble solid, liquid, or gaseous mass circulating in the blood to a site distant from its origin.
• Types of emboli:
  • Gas (e.g., surgery, decompression sickness).
  • Liquid (e.g., amniotic fluid, fat emboli).
  • Solid (e.g., thrombus, atheroma, bone marrow)
  • Foreign bodies (e.g., bullets).
• Origins and sites of embolization:
  • Venous (e.g., DVT to pulmonary arteries).
  • Arterial (e.g., heart or aorta to systemic circulation).
  • Paradoxical (e.g., through a septal defect in the heart).

Infarction

• Definition: Formation of an infarct, a localized area of ischemic necrosis caused by occlusion of the blood supply (mainly arterial).
• Causes:
  • Arterial thrombi or emboli.
• Other less common Causes:
  • Vasospasm.
  • Atherosclerosis expansion.
  • Hemorrhage.
  • External compression (e.g., tumor).
  • Traumatic vascular rupture.
  • Vessel twisting.
  • Venous thrombosis in organs with a single efferent vein.

Infarct Morphology

• Pale: Often roughly wedge-shaped, found in solid organs with a single blood supply (e.g., kidneys, spleen, heart).
• Hemorrhagic: In soft organs with dual blood supply or collaterals (e.g., lungs, bowel, liver).

Infarct Development Factors

• Anatomy of vascular supply (alternative blood supply).
• Rate of occlusion (slow occlusion less likely to cause infarction).
• Tissue vulnerability to hypoxia (neurons, cardiac muscle, fibroblasts).

Hyperemia & Congestion

• Hyperemia: Active process of increased blood flow in an area, due to arteriole dilation, and resulting from inflammation and muscle exercise.
• Congestion: Passive process of impaired outflow of blood from a tissue and caused by cardiac failure or venous obstruction.

Hemorrhage

• Definition: Extravasation of blood due to the rupture of blood vessels.
• Types of hemorrhage:
  • Petechiae.
  • Purpura.
  • Ecchymoses.
  • Hematoma.
  • Hemoptysis.
  • Hematemesis.
  • Melena.
  • Hematochezia.
  • Hematuria.
  • Hemopericardium.
  • Hemorrhage
• Causes of hemorrhage:
  • Vascular diseases (e.g., atherosclerosis, arteritis, aneurysms).
  • Low platelets.
  • Coagulopathy. -Ulcers, tumors, coagulation factors, infarcts, trauma.

Shock

• Definition : Systemic hypoperfusion due to reduction in cardiac output.
• Types:
  • Cardiogenic.
  • Neurogenic.
  • Hypovolemic.
  • Septic.
  • Anaphylactic.
• Stages:
  • Non-progressive.
  • Progressive.
  • Irreversible.